Funds are requested for instrumentation for a peptide synthesis core laboratory at the Joslin Diabetes Center. The Joslin is a combined research institute and patient care facility dedicated to the understanding and treatment of diabetes and related disorders. Research interests are broad, ranging from basic biochemical and molecular mechanisms to the development of treatments for diabetes and its complications. Many projects rely on the availability of a diverse array of peptides and its complications. Many projects rely on the availability of a diverse array of peptides and related depsipeptide analogs. Examples of some ongoing projects are: (1) Characterization of the immune response in Type I diabetes and identification of specific cellular proteins; (2) Elucidation of the mechanism by which the tyrosine protein kinase receptors for insulin, IGF-I and EGF exert their biological effects. Peptide substrates and inhibitors of these proteins are being designed and functional domains mapped by preparation of anti-peptide antibodies. Similar studies are being performed in related signalling systems including the various forms of protein kinase C. Phosphatases responsible for dephosphorylation and reversal of cellular signalling pathways are also being studied with respect to active site specificity, purification, and production of domain specific antibodies; (3) The sequences of a growing number of membrane-associated glucose transporters are being deduced and anti-peptide antibodies are being generated against specific regions for tissue localization and correlations with diabetes; (4) A wide variety of peptide hormone (most notably insulin and glucagon) analogs are being designed to act as suprapotent agonists and antagonists, and are being characterized by 2-D NMR and for target cell specificity of action. The analogs are for investigational use and to test as potential therapeutic agents; (5) Peptide analogs of the extracellular matrix (collagen) are being tested as substrates of various glycosylating enzymes (to determine relative specificities) and for antibody production (for tissue localization and purification); (6) Once the sequence of particular DNA binding proteins have been deduced, peptides corresponding to specific sequences will be used to generate specific antibodies in an attempt to isolate "transcription factors" that regulate mRNA synthesis; (7) Pro- protein processing involves proteolysis at specific sites; for proinsulin the specific endoproteases have been identified and their relative specificities will be tested with peptide prohormone analogs. These are some examples of the many peptides currently needed for ongoing projects at the Joslin Diabetes Center. We foresee a very substantial ongoing need for similar and additional peptides in the future which would be provided by this core facility.